1. Technical Field
The present subject matter is generally directed to the field of microelectronic imager devices and various methods of packaging and manufacturing such devices, and the resulting packaged imager devices.
2. Description of the Related Art
Microelectronic imagers are used in digital cameras, wireless devices with picture capabilities, and in many other applications. Cell phones and Personal Digital Assistants (PDAs), for example, are incorporating microelectronic imagers for capturing and sending pictures. The growth rate of microelectronic imagers has been steadily increasing as they become smaller and produce better images with higher pixel counts.
Microelectronic imagers include image sensors that use Charged Coupled Device (CCD) systems, Complementary Metal-Oxide Semiconductor (CMOS) systems, or other systems. CCD image sensors have been widely used in digital cameras and other applications. CMOS image sensors are also quickly becoming very popular because of their relative lower production costs, higher yields and smaller sizes. CMOS image sensors can provide these advantages because they are manufactured using technology and equipment developed for fabricating semiconductor devices. CMOS image sensors, as well as CCD image sensors, are accordingly “packaged” to protect the delicate components and to provide external electrical contacts.
FIG. 1 is a schematic view of a conventional microelectronic imager 1 with a conventional package. The imager 1 includes a die 10, an interposer 20 attached to the die 10 and a housing 30 attached to the interposer 20. The housing 30 surrounds the periphery of the die 10 and has an opening 32. The imager 1 also includes a transparent cover 40 over the die 10.
The die 10 includes an array of image sensors 12 and a plurality of bond pads 14 that are electrically coupled to the array of image sensors 12. The interposer 20 is typically a dielectric fixture having a plurality of bond pads 22, a plurality of ball pads 24 and wiring 26 that electrically couples the bond pads 22 to corresponding ball pads 24. The ball pads 24 are arranged in an array for surface mounting the imager 1 to a printed circuit board or module of another device. The bond pads 14 on the die 10 are electrically coupled to the bond pads 22 on the interposer 20 by wire bonds 28 to provide electrical pathways between the bond pads 14 and the ball pads 24. The interposer 20 can also be a lead frame or ceramic housing.
The imager 1 shown in FIG. 1 also has an optics unit including a support 50 attached to the housing 30 and a barrel 60 adjustably attached to the support 50. The support 50 can include internal threads 52, and the barrel 60 can include external threads 62 engaged with the threads 52. The optics unit also includes one or more lenses 70 carried by the barrel 60. By rotating the barrel 60, the lens 70 may be properly positioned relative to image sensors 12. Thereafter, the barrel 60 is secured to the housing 30 by, for example, the use of an adhesive.
Manufacturers of imager devices are under constant pressure to reduce costs and improve manufacturing efficiencies and quality to remain competitive in the marketplace. The support 50 and barrel 60 are typically assembled separately for each die 10 individually after the die have been singulated from a wafer and attached to the interposer substrate 20. Therefore, there is a significant need to enhance the efficiency, reliability and precision of packaging microelectronic imagers.
While the subject matter disclosed herein is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the scope of the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.